Final answer:
Brachytherapy is the medical procedure involving the direct implantation of radioactive sources, such as seeds or pellets, into a localized tumor area to treat cancer internally. It allows for a targeted approach that minimizes radiation exposure to surrounding healthy tissue.
Step-by-step explanation:
The implantation of radioactive sources into a localized tumor is known as brachytherapy. This form of internal radiation therapy is used to treat various types of cancer, such as prostate cancer. During the procedure, radioactive pellets or seeds, which may contain isotopes like iodine-125 or palladium-103, are surgically implanted directly at the tumor site. These seeds emit radiation that helps to kill cancer cells while minimizing exposure to surrounding healthy tissue. The small size of these seeds allows for precise delivery of radiation, and their radioactivity diminishes due to their short half-life, reducing long-term radiation exposure. Rods containing radioactive material can also be temporarily inserted for the delivery of internal radiation. While the patient will emit radiation when pellets or seeds are inside their body, those undergoing therapy with rods do not remain radioactive after the treatment.